We obtained evidence for 2 hypotheses: 1) Immune regulation in the brain is site-specific. 2) Local neurochemicals contribute to local control. This work has potentially important clinical implications: 1) It may help to explain the localization and the nature of some major neurologic disorders. 2) It may suggest a new approach to therapeutic control. The initial work was done in disease-free rats. We defined site-specific effects of locally-injected IFN-g. We showed that the injected IFN-g is influenced by local neurochemicals, including Substance P (SP). Now, we aim to show relevance in rats with ongoing CNS disease, using an EAE model. The project is being submitted as an R21 application in accordance with the R21 guidelines: 1) Site-specific immune control, and a role of local neurochemicals, could have major clinical implications, if we can show they are relevant during ongoing CNS disease. 2) Although we have extensive background data, we have do not yet have all the preliminary data that is needed for full-scale R01 support. If the experiments succeed, they will provide it. AIM. Define effect of SP manipulation in EAE and begin mechanistic studies. A. Confirm and extend pilot data showing SP manipulation can be protective (Methods, Exp. 1, 2). B. Show effects of SP manipulation are receptor-mediated, by appropriate receptors (Exp. 3, 4). C. Follow up selected findings, to set framework for, and begin, mechanistic studies (Exp. 5, 6). This is an amended application, revised in response to the reviewers' comments. Methods include intra-cerebral injection of cytokine (IFN-gamma) and pharmacological agents (SP, agonists, antagonists), antibody staining of tissue sections, and computer-assisted image analysis. Rats are used. [unreadable] [unreadable]